Add JUnit 5 Expect extension

extensions/junit5/pom.xml

@@ -0,0 +1,55 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project
+    xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.google.truth.extensions</groupId>
+    <artifactId>truth-extensions-parent</artifactId>
+    <version>HEAD-SNAPSHOT</version>
+  </parent>
+  <artifactId>truth-junit5-extension</artifactId>
+  <name>Truth Extension for JUnit Jupiter</name>
+  <description>
+    An extension for JUnit Jupiter to use soft assertions with Truth test assertion framework
+  </description>
+  <dependencies>
+    <dependency>
+      <groupId>com.google.truth</groupId>
+      <artifactId>truth</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.platform</groupId>
+      <artifactId>junit-platform-testkit</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.opentest4j</groupId>
+      <artifactId>opentest4j</artifactId>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <artifactId>maven-javadoc-plugin</artifactId>
+      </plugin>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

extensions/junit5/src/main/java/com/google/common/truth/junit5/Expect.java

@@ -0,0 +1,82 @@
+package com.google.common.truth.junit5;
+
+import com.google.common.truth.FailureStrategy;
+import com.google.common.truth.StandardSubjectBuilder;
+import org.junit.jupiter.api.extension.AfterEachCallback;
+import org.junit.jupiter.api.extension.Extension;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.api.extension.ParameterContext;
+import org.junit.jupiter.api.extension.ParameterResolver;
+import org.opentest4j.MultipleFailuresError;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * An <tt>Extension</tt> that provides a {@link StandardSubjectBuilder} parameter to test methods.
+ *
+ * <p>Assertion failures on the given <tt>StandardSubjectBuilder</tt> will not immediately fail;
+ * instead, failures will be reported at the <em>end</em> of the test.
+ *
+ * <p>Usage:
+ *
+ * <pre>
+ * @ExtendWith(Expect.class) // or system property junit.jupiter.extensions.autodetection.enabled=true
+ * ...
+ *     @Test
+ *     public void test(StandardSubjectBuilder expect) {
+ *         ...
+ *     }
+ * </pre>
+ */
+public class Expect implements Extension, ParameterResolver, AfterEachCallback {
+  @Override
+  public boolean supportsParameter(ParameterContext parameterContext, ExtensionContext extensionContext) {
+    return parameterContext.getParameter().getType() == StandardSubjectBuilder.class;
+  }
+
+  @Override
+  public StandardSubjectBuilder resolveParameter(ParameterContext parameterContext, ExtensionContext extensionContext) {
+    ExtensionContext.Store store = extensionContext.getStore(ExtensionContext.Namespace.create(Expect.class));
+    return store.getOrComputeIfAbsent(extensionContext.getUniqueId(), key -> new Holder(), Holder.class).get();
+  }
+
+  @Override
+  public void afterEach(ExtensionContext context) {
+    ExtensionContext.Store store = context.getStore(ExtensionContext.Namespace.create(Expect.class));
+    Holder holder = store.get(context.getUniqueId(), Holder.class);
+    List<AssertionError> failures = null;
+    if (holder != null) {
+      synchronized (holder) {
+        failures = holder.failures;
+        if (failures == null) {
+          throw new IllegalStateException();
+        }
+        holder.failures = null;
+      }
+    }
+    if (failures != null && !failures.isEmpty()) {
+      throw failures.size() == 1 ? failures.get(0) : new MultipleFailuresError(null, failures);
+    }
+  }
+
+  private static class Holder implements FailureStrategy, ExtensionContext.Store.CloseableResource {
+    private List<AssertionError> failures = new ArrayList<>();
+
+    private StandardSubjectBuilder get() {
+      return StandardSubjectBuilder.forCustomFailureStrategy(this);
+    }
+
+    @Override
+    public synchronized void fail(AssertionError failure) {
+      failures.add(failure);
+    }
+
+    @Override
+    public synchronized void close() {
+      if (failures != null) {
+        throw new IllegalStateException();
+      }
+    }
+  }
+}

extensions/junit5/src/main/resources/META-INF/services/org.junit.jupiter.api.extension.Extension

@@ -0,0 +1 @@
+com.google.common.truth.junit5.Expect

extensions/junit5/src/test/java/com/google/common/truth/junit5/ExpectTest.java

@@ -0,0 +1,59 @@
+package com.google.common.truth.junit5;
+
+import static org.junit.platform.engine.discovery.DiscoverySelectors.selectClass;
+import static org.junit.platform.testkit.engine.EventConditions.event;
+import static org.junit.platform.testkit.engine.EventConditions.finishedWithFailure;
+import static org.junit.platform.testkit.engine.EventConditions.test;
+
+import com.google.common.truth.StandardSubjectBuilder;
+import org.assertj.core.api.Condition;
+import org.junit.jupiter.api.MethodOrderer.OrderAnnotation;
+import org.junit.jupiter.api.Order;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestMethodOrder;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.platform.testkit.engine.EngineTestKit;
+import org.junit.platform.testkit.engine.Events;
+import org.opentest4j.MultipleFailuresError;
+
+public class ExpectTest {
+  @Test
+  public void testExtension() {
+    Events events = EngineTestKit.engine("junit-jupiter")
+        .selectors(selectClass(TestCase.class))
+        .execute()
+        .testEvents()
+        .assertStatistics(stats -> stats.started(3).failed(2));
+    events.succeeded().assertEventsMatchExactly(event(test("testSuccess")));
+    events.failed().assertEventsMatchExactly(
+        event(test("testOneFailure"), finishedWithFailure(new Condition(t -> t instanceof AssertionError && !(t instanceof MultipleFailuresError), "AssertionError"))),
+        event(test("testTwoFailures"), finishedWithFailure(new Condition(MultipleFailuresError.class::isInstance, "MultipleFailuresError"))));
+  }
+
+  @ExtendWith(Expect.class)
+  @TestMethodOrder(OrderAnnotation.class)
+  static class TestCase {
+    @Test
+    @Order(1)
+    public void testSuccess(StandardSubjectBuilder expect) {
+      expect.that(0).isEqualTo(0);
+      expect.that(1).isEqualTo(1);
+    }
+
+    @Test
+    @Order(2)
+    @ExtendWith(Expect.class)
+    public void testOneFailure(StandardSubjectBuilder expect) {
+      expect.that(0).isEqualTo(1);
+      expect.that(1).isEqualTo(1);
+    }
+
+    @Test
+    @Order(3)
+    @ExtendWith(Expect.class)
+    public void testTwoFailures(StandardSubjectBuilder expect) {
+      expect.that(0).isEqualTo(1);
+      expect.that(1).isEqualTo(0);
+    }
+  }
+}

extensions/pom.xml

@@ -22,5 +22,6 @@
     <module>re2j</module>
     <module>liteproto</module>
     <module>proto</module>
+    <module>junit5</module>
   </modules>
 </project>

pom.xml

@@ -79,6 +79,26 @@
         <artifactId>junit</artifactId>
         <version>4.12</version>
       </dependency>
+      <dependency>
+        <groupId>org.junit.jupiter</groupId>
+        <artifactId>junit-jupiter-api</artifactId>
+        <version>5.6.2</version>
+      </dependency>
+      <dependency>
+        <groupId>org.junit.jupiter</groupId>
+        <artifactId>junit-jupiter-engine</artifactId>
+        <version>5.6.2</version>
+      </dependency>
+      <dependency>
+        <groupId>org.junit.platform</groupId>
+        <artifactId>junit-platform-testkit</artifactId>
+        <version>1.6.2</version>
+      </dependency>
+      <dependency>
+        <groupId>org.opentest4j</groupId>
+        <artifactId>opentest4j</artifactId>
+        <version>1.2.0</version>
+      </dependency>
       <dependency>
         <groupId>com.google.gwt</groupId>
         <artifactId>gwt-user</artifactId>
@@ -322,7 +342,7 @@
         </plugin>
         <plugin>
           <artifactId>maven-surefire-plugin</artifactId>
-          <version>2.12.4</version>
+          <version>2.22.2</version>
         </plugin>
         <plugin>
           <artifactId>maven-enforcer-plugin</artifactId>